Magnetization and magnetoelectric effect in Bi 1 − x La x FeO 3 ( 0 ≤ x ≤ 0.15 )

We report on magnetization and magnetocapacitance measurements in the ${\text{Bi}}_{1\ensuremath{-}x}{\text{La}}_{x}{\text{FeO}}_{3}$ series for $0\ensuremath{\le}x\ensuremath{\le}0.15$. We confirm that doping with La reduces the threshold magnetic field ${H}_{\text{c}}$ for cancelling the magnetic spiral phase, and we show that ${H}_{\text{c}}$ decreases as the La content increases up to $x=0.15$, which is the highest concentration for maintaining the noncentrosymmetric rhombohedral structure of ${\text{BiFeO}}_{3}$. Measurements of the dielectric constant as a function of magnetic field in the series also show a maximum magnetocapacitance for $x=0.15$.